RainLab\Pages\Classes\Page::generateFilenameFromCode PHP Method

    protected function generateFilenameFromCode()
    {
        $dir = rtrim($this->getFilePath(''), '/');
        $fileName = trim(str_replace('/', '-', $this->getViewBag()->property('url')), '-');
        if (strlen($fileName) > 200) {
            $fileName = substr($fileName, 0, 200);
        }
        if (!strlen($fileName)) {
            $fileName = 'index';
        }
        $curName = trim($fileName) . '.htm';
        $counter = 2;
        while (File::exists($dir . '/' . $curName)) {
            $curName = $fileName . '-' . $counter . '.htm';
            $counter++;
        }
        return $curName;
    }